A high-voltage circuit breaker known from U.S. Pat. No. 4,499,350 has a main current path which can be disconnected by an interrupter unit. A secondary current path can be routed in parallel with the main current path, in which a switch and a closing resistor are connected in series with one another in this secondary current path. The closing resistor can be connected into the circuit shortly before the closing of the contact arrangement of the interrupter unit such that the current flows through the secondary current path with the closing resistor, shortly before the main current path is closed. In consequence, the closing resistor can be inserted into the circuit under load. A moving interrupter contact of the interrupter unit can be driven by a drive element via levers and angle elements. A driven contact of the switch can likewise driven by the same drive unit. The driven contact of the switch interacts with a likewise moving opposing contact of the switch, which is prestressed in the direction of the contact by means of a spring. When the high-voltage circuit breaker closes, the switch closes before the interrupter unit. After the switch has closed, the interrupter unit closes, as a result of which the secondary current path can be bridged via the main current path.
During opening of the high-voltage circuit breaker, the switch opens before the interrupter unit, as a result of which the current can be interrupted by the interrupter unit. This can be achieved by the driven contact moving at a higher speed than the opposing contact, on which the force of the spring acts.
Known high-voltage circuit breakers include a large number of individual parts to operate the interrupter unit and the switch. In addition, during opening of the high-voltage circuit breaker, the spring for the switch governs the time at which this opens.
Another gas-insulated, encapsulated high-voltage circuit breaker is disclosed in U.S. Pat. No. 2,117,975. This known high-voltage circuit breaker has an interrupter unit. A switch and a closing resistor are arranged in parallel with this interrupter unit, with the switch being connected in series with the closing resistor. A contact of the switch is moved along an axis in order to connect the closing resistor.
The foregoing US Patents are hereby incorporated by reference in their entireties.